Polyvinyl alcohol (PVOH) binder fibers are useful for increasing the strength of paper products, although fiber cost can be prohibitive for many applications. Fiber cost can be mitigated by introducing fillers that are cheaper than PVOH. However, alternative fibers that incorporate recycled materials as fillers may not be suitable for white paper products because fibers produced are dark in color.
Bright fillers, such as precipitated calcium carbonate or other minerals, are commonly compounded with plastics, such as polypropylene. Polymers compounded with fillers may require low moisture content, depending on the polymer/filler combination. For example, fine, bright cellulose particles generally need to be dry to be compatible with plastic. PVOH is less restrictive on moisture content than plastics. Fillers in water may be combined with PVOH and formed into fibers and films without drying beforehand. When PVOH is the polymer, fine cellulose particles generally do not need to be pre-dried before mixing and forming fibers and films.
Based on the foregoing, there exists a need for cost-effective, water-based, filled PVOH fibers that can be incorporated into white paper products. Accordingly, it is to solving this and other needs the present invention is directed.